Doping of the ferroelec. Sm-C* phase with bent-shaped mols. induces the antiferroelec. Sm-C*A phase. The effect was obsd. by electrooptic and dielec. measurements in systems with weak interlayer interactions in which the relative strength of anticlinic-synclinic order between mols. in adjacent layers is easily controlled by external factors. FTIR spectroscopy studies suggest that the bent-shaped mols. are not flat. They reorient upon the elec. field-induced antiferroelec.-ferroelec. transition to adopt a position in which the av. direction of the carbonyl groups is in the smectic plane and a bending tip along the C2 symmetry axis. [on SciFinder(R)]